Cheapest priced copy (GRN Guild Kit): $0.59 at Card Kingdom, near mint, their price list as of .
Brightflame 
Sorcery · Rare · Ravnica: City of Guilds · #194
Radiance — Brightflame deals X damage to target creature and each other creature that shares a color with it. You gain life equal to the damage dealt this way.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.59 to $1.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| GRN Guild Kit | 87 | Rare | $0.59 | — |
| Ravnica: City of Guilds | 194 | Rare | $0.69 | $1.99 |
6 rulings from Wizards of the Coast
- 1 October 2005Only one creature is targeted. If that creature leaves the battlefield or otherwise becomes an illegal target, the entire spell doesn’t resolve. No other creatures are affected.
- 1 October 2005You gain life equal to the total damage dealt by Brightflame to all creatures. You don’t gain life for any damage that was prevented.
- 1 October 2005All creatures that share a color are affected, even your own.
- 1 October 2005You check which creatures share a color with the target when the spell resolves.
- 1 October 2005A creature “shares a color” with any creature that is at least one of its colors. For example, a green-white creature shares a color with creatures that are green, white, green-white, red-white, black-green, and so on.
- 1 October 2005If it targets a colorless creature, it doesn’t affect any other creatures. A colorless creature shares a color with nothing, not even other colorless creatures.